Can Trout and Cows Coexist?
Rotational grazing may be an acceptable alternative to fencing livestock out of streams, say researchers at UW–Madison and the Wisconsin Department of Natural Resources. The researchers are comparing the ecological effects of grassy buffer strips, woody buffer strips, continuous grazing and rotational grazing along trout streams in southwestern Wisconsin.
A team of researchers including John Lyons, researcher and watershed ecologist with the DNR, and Laura Paine, agronomy research specialist with the College of Agricultural and Life Sciences, and others at UW–Madison are evaluating fish communities, aquatic insects, stream bank conditions, forage production, and wildlife species on 19 farms in the region.
“We are learning a lot about the interaction between biotic systems and farming systems; what is required for high quality fish habitat, and the constraints that farmers have,” said Paine. “Instead of working at odds toward often opposing goals, we are looking at ways to work together to find practices which are acceptable to both, and that farmers can adopt practically and profitably.”
Results from the first year of the study indicate that rotational grazing is nearly as effective as grassy buffer strips and is an improvement over continuously grazed strips in terms of the resulting detrimental effects on trout habitats. However, the ecological condition of the entire watershed of a particular stream appears to be a more important factor than local grazing practices when trying to guage the health of fish populations and other aquatic species.
Although there was less bank erosion and better trout habitat on the rotationally grazed sites than on continuously grazed sites, researchers did not find more trout in the stream near rotationally grazed strips.
“Rotational grazing does develop more sod than continuous grazing on banks, but if you’re going to have a big influence on fish it will take more than 5 or 10 percent of farms in the watershed to make a difference,” said Lyons.
Grassy and woody buffers had the highest trout populations. According to Lyons, there are arguments for and against wooded buffers. Although soil may be less stable on wooded banks than in grassy areas, trees in the wooded strips fall into the stream and provide habitat for fish. Also, trees shade the stream and keep water cool, which is important for trout, he said. However, anglers prefer fishing in grassy areas rather than woods.
According to Paine, the study indicates that no single management approach will meet the goals of all farmers, fishermen, and wildlife managers.
“We can provide broader benefits by applying a patchwork of different types of environmentally sound management over a whole watershed,” Paine said. “The idea of watershed management is looking at the ecosystem from a landscape scale, rather than focusing on individual pieces of land or individual land owners.”
The researchers are continuing to collect data in 1997 and may continue the study through 1998. Others involved in the project at UW–Madison include agronomist Dan Undersander, wildlife ecologist Chris Ribic, and graduate students Brian Weigel, Roz Renfrew and Erik Chapman.